When objects are conveyed, it is often required to establish the amount or quantity of the objects that has been moved. The question of the conveyed amount arises for conveyor belts in quarries, in agriculture or in the blast furnace industry and even for conveyor belts used in energy production or in port facilities. In many of these industry sectors, there is a particular requirement during a filling or emptying process to record as a volume or mass, the amount of material moved by means of a conveyor belt, for example in order then to produce automated invoices for example or to stop the filling process at the right time.
Belt scales, which continually detect the force currently exerted by the weight of the conveyor belt and of the conveyed medium, can be used, for example, to determine the conveyed amount of an object.
Using belt scales to monitor conveyor systems, however, can result in operational variations that may falsify the measurement result. In addition, the measuring apparatus for using a belt scale must be incorporated directly in the design of the conveying means, and it is difficult to retrofit to existing installations.